Earning 750 crystals to buy one piece of novice armor + a type 10 aug seems a bit high. My team was a 4 person group of t3 geared people (sk/clr/2xmag) and I got 7 crystals in ~30 mobs which took about 20 minutes. I am not too good at math, but I think that's ~3000 mobs before I can get 1 piece of gear on 1 toon.
I suggest maybe increase radiant crystal's drop rate and or reward crystals for completing a task. Or take out the armor merchant and have the armor random drop and just buy type 10 augs the way the current system works.